There's actually a script add-on for Firefox and Chrome (though I can only find it for Chrome at the moment, oddly enough) that has allowed chain commands for years. Really surprised it never caught on more as that seems to be the number one feature request.

Here it is for Chrome if you wanna try it out (though like I said, it seems that with the recent change that removes aircraft 'circling' waypoints, it inadvertently disabled this important chain command feature of the script.